Various techniques have been proposed in order to reduce the power consumption of a system provided with, for example, a microprocessor. For example, the following technique has been known: a clock is set to a low speed in a sleep state (power saving state) in which the operation of the system is temporarily stopped, and then the clock is set to a high speed when the system resumes from the sleep state and executes a process.
However, in the technique according to the related art, the operation state of the system after resuming from the sleep state is set without any consideration for the time required for processing executed after the system resumes from the sleep state. Therefore, in some cases, it is difficult to appropriately reduce the power consumption of the system. For example, when the time required for the processing executed after the system resumes from the sleep state is short, the clock is set to a high speed although power required for the system is small, which results in unnecessary power consumption. Therefore, it is difficult to appropriately reduce power consumption.